JPH029116A - Forming method for film on semiconductor substrate - Google Patents

Abstract

PURPOSE:To equalize the contact amount of reaction gas at positions of groups of materials to be treated and to make the process uniform by regulating the rotating operation of a reaction gas discharger suspended in the sidewise direction of the groups and reaction gas discharging flow rate from the discharger. CONSTITUTION:A reaction gas discharge tube 16 and a boat elevator 15 are respectively mounted rotatably at axial centers by a discharge tube rotating mechanism 21 and a wafer rotating mechanism 22. It is treated during a process while rotating the tube 16 and the group 13 of semiconductor wafers. The mechanisms 21, 22 are controlled to be driven and at the valves of flow rate regulating valves 19 by a reaction control mechanism 23. Thus, since the reaction gas discharging time to the peripheral edge of the group 13 is increased as compared with that at the center of the group 13, the contact amounts of the gas at the center and the peripheral edge of the wafer are equalized. Thus, uniform processes are conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a film forming method, and particularly to a film forming method on a semiconductor substrate using a vertical heat treatment apparatus.

(Conventional technology) In recent years, heat treatment equipment used in the thermal diffusion process and film formation process in the semiconductor device manufacturing process has been developed to save space, save energy, increase the diameter of semiconductor wafers to be processed, and increase automation. Vertical heat treatment equipment has been developed for reasons such as ease of χ·l reactions.

As this vertical heat treatment apparatus, for example, in a so-called ho-no-wall type vertical heat treatment apparatus in which a heating mechanism is placed outside a reaction vessel, a large number of processing objects, such as semiconductor wafers, are stacked on shelves at a predetermined arrangement pitch inside the reaction vessel. However, a reaction gas depending on the processing content, such as SiH2Cn2 for performing Si epitaxial growth, is introduced into the reaction vessel, and the processing is performed at a predetermined temperature condition, for example, 1000°C to 1100°C.

In the film formation process using this vertical heat treatment equipment, uniform film formation is achieved by how uniformly the reaction gas contacts the object to be processed.
Second, since it is a major factor, various techniques have been studied regarding the method of discharging the reaction gas.

For example, as shown in FIG. 6, a cylindrical reaction gas discharge pipe 2 is disposed in the side direction of an object to be processed, such as a semiconductor unit 1, housed in a reaction vessel, and a large number of discharges are provided in this discharge pipe. A method is known in which uniform processing is performed by discharging reaction gas 4 from outlet 3 and processing semiconductor wafer group 1 while rotating it.

Also known are a method in which reactive gas discharge tubes are revolved around a group of semiconductor wafers for processing, and a method in which a large number of discharge tubes are disposed around a group of semiconductor wafers along the side surface direction.

(Problem to be Solved by the Invention) However, in any of the heat treatment methods described above, a constant flow rate of reactive gas is continuously discharged from the discharge part, so that the reactive gas is The amount of contact is different, and the amount of reaction is particularly large at the center of the semiconductor wafer (
However, the objective of uniform processing could not be completely satisfied. For example, when Si epitaxial growth is performed, there is a problem in that the film thickness at the center of the semiconductor wafer is thicker than at the peripheral part, as shown in FIG. 7, and uniform film formation cannot be performed.

The present invention has been made in order to solve the above-mentioned problems, and the discharge direction of the reaction gas and the discharge flow rate of the reaction gas are set to 5.
! It is an object of the present invention to provide a method for forming a film on a semiconductor substrate, which enables uniform processing by performing processing while adjusting I.

[Structure of the Invention] (Means for Solving the Problems) In the method of forming a film on a semiconductor substrate of the present invention, a large number of objects to be processed are stacked and stored at a predetermined arrangement pitch in a reaction vessel, and a group of objects to be processed are stacked. In a method for forming a film on the group of objects to be treated by discharging a reactive gas from a gas discharge section rotatably installed vertically facing a side surface in the arrangement direction, the amount of contact of the reactive gas at each part of the group of objects to be treated is The method is characterized in that the film is formed while rotating the gas discharge section so that the amount of the gas is uniform.

(Function) The present invention adjusts the rotational operation of a reactive gas discharge section vertically installed in the side direction of a group of objects to be treated and the flow rate of the reactive gas discharged from this gas discharge section. By equalizing the amount of contact with the reaction gas at each location, uniform processing becomes possible.

(Example) Hereinafter, an example of the method of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a vertical heat treatment apparatus to which the method of the present invention is applied, in which a heating mechanism 12 is disposed outside a cylindrical reaction vessel 11 made of, for example, quartz glass, which maintains a vacuum. .

Further, in the center of the reaction vessel 11, a wafer boat 14 in which a large number of objects to be processed, such as semiconductor wafers 13a, are stacked on shelves at a predetermined arrangement pitch is mounted on an elevating mechanism, such as a boat elevator 15.

A small cylindrical reaction gas discharge pipe 16 is vertically installed on the side surface of the group of semiconductor wafers 13 in the arrangement direction, and a reaction gas discharge pipe 16 in the form of a small cylinder is provided on the outer periphery of the reaction gas discharge pipe 16 in a direction substantially parallel to each of the semiconductor wafers. A reaction gas corresponding to the processing content is introduced into the reaction vessel 11 through a large number of discharge ports 17 formed in the vertical direction to form a gas flow. The reaction gas is supplied to the reaction gas discharge pipe 16 from the reaction gas source 18 through the flow rate adjustment valve 1.
9, and the spent gas is exhausted through an exhaust port 20 provided at the bottom of the container 11.

The reaction gas discharge pipe 16 is operated by a discharge pipe rotation mechanism 21.
In addition, the boat elevator 15 is mounted so as to be rotatable about its respective axial direction by a wafer rotation mechanism 22.
During the processing, the reaction gas discharge pipe 16 and the semiconductor wafer group 13 are rotated.

Further, the drive control of the discharge pipe rotation mechanism 21 wafer, the rotation mechanism 22 and the valve control of the flow rate adjustment valve 19 are configured to be controlled by the reaction control mechanism 23.

A method of processing semiconductor wafers using such a vertical heat treatment apparatus will be described below.

After the wafer boat 14 is transferred onto the boat elevator 15 by a transfer mechanism (not shown), the boat elevator 1
5 to raise the semiconductor wafer n13 to a predetermined height within the reaction chamber 11.

Then, the interior of the reaction chamber 11 is maintained at a predetermined degree of vacuum and the heating machine 12 is heated.
After setting the temperature atmosphere to a predetermined temperature, for example, 1000° C. to 1100° C. if Si epitaxial growth is to be performed, a predetermined reactive gas such as 5iHzCJ2z or the like is discharged from the reaction gas discharge port 17 to start the process. .

During the processing, as shown in FIG. 2, the semiconductor wafer group 13 and the reactive gas discharge pipe 16 are rotated at a rotational speed of 10 rpm, for example, and the flow rate of the reactive gas is adjusted by the flow rate regulating valve 19. Alternatively, the discharge pipe 16 may be fixed and only the gas discharge port may be moved.

As a method for controlling the rotation of the group 13 and the reactive gas discharge pipe 16 and controlling the amount of reactive gas discharged to these semiconductor wafers, for example, the semiconductor wafer group 13 and the reactive gas discharge pipe 16 are rotated in opposite directions, and the reactive gas discharge pipe 16 The discharge amount and the reaction gas discharge pipe are adjusted so that the discharge amount when the discharge port 17 of the semiconductor wafer group 13 faces toward the peripheral edge direction aSc is larger than when the discharge port 17 faces toward the center of the semiconductor wafer group 13. Controls the rotation of 16.

As an example, as shown in FIG.
The flow rate adjustment valve 19 is controlled so as to discharge the reaction gas only during a deflection angle of 0, with one peripheral edge direction a as a discharge start point and the other peripheral edge direction C as a discharge end point,
On the other hand, the rotational operation of the reactive gas discharge pipe 16 is controlled so as to be temporarily stopped when the discharge port 17 faces the semiconductor wafer group peripheral edge directions a and C.

By performing processing under such control, the reaction gas discharge time to the periphery of the group of semiconductor wafers is longer than that to the center of the group of semiconductor wafers, so the amount of contact of the reaction gas between the center and the periphery of the wafers is reduced. are equal, and uniform processing can be performed.

As another control method, as shown in FIG. 4, the rotational speed of the reactive gas discharge pipe 16 at the discharge deflection angle θ is kept constant, and the discharge amount of the reactive gas is varied from the peripheral direction a to the central part of the semiconductor wafer. It may be controlled so that it gradually decreases toward .

As another control method, as shown in FIG. 5, the discharge operation of the reactive gas is performed in a pulsed manner, and the timing of discharge of the reactive gas is adjusted such that the rotational operation of the reactive gas discharge pipe 16 is stopped when the reactive gas is discharged. Control may be performed to synchronize the rotational movements of the tubes.

At this time, the reaction gas ejection time of one pulse, that is, the pulse width of the ejection operation, is made smaller toward the center direction C of the semiconductor wafer group 13.

By controlling the discharge operation in a pulsed manner as described above, the flow rate control of the reaction gas can be realized using a simple mechanism such as an on-off valve. Moreover, by installing this opening/closing valve near the reactive gas discharge section, it is possible to ensure response in flow rate adjustment.

In this way, in each of the above-mentioned embodiments, uniform processing can be performed by controlling the rotational operation of the reactive gas discharge pipe 16 and the discharge flow rate of the reactive gas according to the processing conditions. .

In the above-mentioned embodiment, the rotational operation of the reactive gas discharge pipe 16 and the flow rate of the discharged amount of the reactive gas are controlled, but the rotational speed of the semiconductor wafer may be controlled at the same time, and each of these operations may be controlled. differs depending on the processing conditions such as the size of the object to be processed and the processing details. Further, the present invention is applicable to various vertical heat treatment apparatuses such as those for Si epitaxial growth, CVD, and thermal diffusion.

[Effects of the Invention] As explained above, according to the heat treatment method of the present invention, it is possible to uniformly treat the object to be treated.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a vertical heat treatment apparatus according to an embodiment to which the method of the present invention is applied, and FIG. 2 is for explaining the rotational operation of a group of semiconductor wafers and the rotational operation of a reaction gas discharge pipe in FIG. 1. , FIG. 3 is a diagram showing a control example of the rotational operation of the reaction gas discharge pipe and the discharge operation of the reaction gas in the embodiment, and FIGS. 4 and 5 are diagrams showing other control examples of FIG. 3. FIG. 6 is a diagram for explaining a processing method in a conventional vertical heat treatment apparatus, and FIG. 7 is a diagram showing a film thickness distribution of a semiconductor wafer subjected to Si epitaxial processing by the conventional apparatus. 11... Reaction chamber, 12... Heating mechanism,
13... Semiconductor wafer group, 16... Reactive gas discharge pipe, 17... Reactive gas discharge port, 19
...Reactant gas flow rate adjustment valve, 21...Discharge pipe rotation mechanism, 22...Wafer rotation mechanism, 23
...Reaction control mechanism.

Claims (1)

[Scope of Claims] A large number of objects to be processed are stacked and housed at a predetermined arrangement pitch in a reaction container, and a reaction gas is discharged from a gas discharge section rotatably installed vertically facing the side surface in the arrangement direction of the group of objects to be processed. The method for depositing a film on the group of objects to be processed by discharging the group of objects is characterized in that processing is performed while rotating the gas discharge section so that the amount of reaction gas in contact with each part of the group of objects to be processed is uniform. A method for forming a film on a semiconductor substrate.